Derivation of Resonant Period for Soft Switching by Linearizing Output Capacitance of Switching Device

Many soft switching techniques utilize the resonance between an inductor and parasitic output capacitor of switching device. However, output capacitance has nonlinear characteristics depending on drain-source voltage which obscure the resonant period. The proposed method estimates the resonant period by linearizing output capacitance. The method can be applied to the bridge-type converter which utilizes resonance for soft switching. Simulation and experiment with a 3-kVA prototype half bridge auxiliary resonant commutated pole inverter were implemented to verify the proposed method.